This invention relates generally to shock isolators and, more specifically, to a shock isolator that uses an elastomer damper that remains in a relaxed condition until a dynamic force is applied to the system.
In the mounting of sensitive equipment in vehicles such as ships or the like it is often necessary to provide some type of isolator or shock mount to the cabinet of the equipment in order to minimize the chances of the equipment being damaged by shock and vibration forces. Because of there inherent damping characteristics a preferred material for use in isolators are elastomers. However, one of the problems with the use of elastomers in isolators is that some of the elastomer materials creep when subjected to a continuous static force. This makes it difficult to have an elastomer to both support the weight of the cabinet and dynamically respond to the vibration and shock forces. One of the difficulties is as the elastomer reaches a deformed state under the static load the equipment supported thereon is repositioned. In addition, with the equipment in the new position the elastomer dynamic damping response to the vibration and shock forces can change thus altering the effectiveness of the isolator in protecting the equipment from shock and vibration. The present invention provides a compact isolator that includes a belleville washer for normally supporting the entire static weight of the equipment with the belleville washer toggleable from a load support position to a non-support position where both the weight of the equipment and the dynamic forces on the equipment are absorbed by the elastomer to prevent shock and vibration forces from damaging the equipment.
Briefly, the present invention comprises a shock isolator having a spring member, such as a belleville washer for supporting static weight with the belleville washer toggleable between a support condition and a non-support condition with the belleville washer having a collapse force that is sufficiently high so that the belleville washer can support a static load without collapsing to maintain an elastomer damping material in a condition free or substantially free of static forces. When a dynamic force and the static force exceeds the collapse force of the belleville washer the belleville washer collapses leaving only the elastomer to respond to both the static and the dynamic forces. As the elastomer damps the dynamic forces of shock and vibration, the forces on the equipment eventually reach a level where a belleville expansion force exceeds the combined static and dynamic forces on the equipment causing the belleville washer to toggle back to the load support condition to again support the load in condition where the elastomer is free or substantially free of static forces.